I called it serious, because the code just won't work in Rails 2.0

You need to add the form's authenticity token to the params before Rails 2.0 will accept it:

authenticity_token=<%= form_authenticity_token %>

I simply added this string after a "?" after 'myresponse' in line 6 of the sample code.

In the first code block, the current version of rails enforces security with an authentication token. The default call produced here is a post which triggers an InvalidAuthenticityToken error.

<p><a href="#" onclick="prototypeAlert( );">Call with Prototype</a></p>
<script type="text/javascript">
function prototypeAlert( ) {
new Ajax.Request('/chapter2/myresponse', { onSuccess: function(request) {
alert(request.responseText);
}})
}
</script>

It is easily fixed by adding "method: 'get'," to the new Ajax.Request call, like this:

<p><a href="#" onclick="prototypeAlert( );">Call with Prototype</a></p>
<script type="text/javascript">
function prototypeAlert( ) {
new Ajax.Request('/chapter2/myresponse', { method: 'get', onSuccess: function(request) {
alert(request.responseText);
}})
}
</script>

The code only renders the time and one doesn't get a chance to click on a link. Thus, it seems to be an issue in the controller action on page 34:

def get_time

# This line generates an error message.
sleep 1.second

# This line just renders the text within the view time text in the
# without displaying the link.
render :text => Time.now

end

Thus, the code on page 37 fails to execute successfully.